Acoustic Echo Cancellation Detector for VoIP Systems

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Solution Overview

Problem

Existing telephony systems face challenges in accurately detecting the presence of platform acoustic echo cancellers (AECs), leading to potential voice quality degradation and increased CPU load due to cascaded AEC operations, especially in VoIP communications.

Innovation Solution

An echo cancellation detector is introduced, comprising a comparison generator and a decision unit to determine the presence of a first AEC by comparing the frequency spectra of far-end and near-end signals, allowing a second AEC to be controlled based on this determination to either enable or disable its operation, thereby avoiding interference with platform AECs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a user application AEC operates on a platform that also has a platform AEC, then echo cancellation capability is enhanced, but voice quality deteriorates and CPU load increases due to cascaded AEC operations

Engineering Contradiction:

Improveecho cancellation capabilityVSAvoidvoice quality

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The system uses the platform AEC's own output signals (near-end signal and far-end signal) to self-detect its presence and performance through spectral comparison, enabling automatic control of the user application AEC without external intervention or additional hardware

Inventive Principle:

Principle #25Self-service

2Reliability

If a user application AEC operates on a platform that also has a platform AEC, then echo cancellation capability is enhanced, but CPU load increases due to cascaded AEC operations

Engineering Contradiction:

Improveecho cancellation capabilityVSAvoidCPU load

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs self-detection by comparing spectral characteristics of signals already present in the system, eliminating the need for additional detection hardware or external testing equipment, thereby minimizing additional CPU overhead

Inventive Principle:

Principle #25Self-service

3Device complexity

If the presence of platform AEC is detected using vendor-provided API information, then device complexity is reduced, but detection reliability deteriorates due to dependency on vendor implementation

Engineering Contradiction:

Improvedetection mechanism simplicityVSAvoiddetection accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent replaces the mechanical/API-based detection method with a signal-processing-based detection method, substituting direct hardware/software interface dependencies with physical signal analysis that is independent of vendor implementation details

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11601554B2Detection of acoustic echo cancellation

Publication Date: 2023.03.07 IMAGINATION TECH LTD

AI summary

An echo cancellation detector for controlling an acoustic echo canceller that is configured to cancel an echo of a far-end signal in a near-end signal in a telephony system, the echo cancellation detector comprising a comparison generator configured to compare the far-end signal with the near-end signal, a decision unit configured to make a determination about a first acoustic echo canceller based on that comparison and a controller configured to control an operation of a second acoustic echo canceller in dependence on the determination.